Schottky barrier height (SBH) engineering of contact structures is a primary challenge to achieve high performance in nanoelectronic and optoelectronic applications. Although SBH can be lowered through various Fermi-level (FL) unpinning techniques, such as a metal/interlayer/semiconductor (MIS) structure, the room for contact metal adoption is too narrow because the work function of contact metals should be near the conduction band edge (CBE) of the semiconductor to achieve low SBH. Here, we propose a novel structure, the metal/transition metal dichalcogenide/semiconductor structure, as a contact structure that can effectively lower the SBH with wide room for contact metal adoption. A perpendicularly integrated molybdenum disulfide (MoS 2 ) interlayer effectively alleviates FL pinning by reducing metal-induced gap states at the MoS 2 /semiconductor interface. Additionally, it can induce strong FL pinning of contact metals near its CBE at the metal/MoS 2 interface. The technique using FL pinning and unpinning at metal/MoS 2 /semiconductor interfaces is first introduced in the MIS scheme to allow the use of various contact metals. Consequently, significant reductions of the SBH from 0.48 to 0.12 eV for GaAs and from 0.56 to 0.10 eV for Ge are achieved with several different contact metals. This work significantly reduces the dependence on contact metals with lowest SBH and proposes a new way of overcoming current severe contact issues for future nanoelectronic and optoelectronic applications.
Bibliographical noteFunding Information:
This work was supported, in part, by the Technology Innovation Program within the Ministry of Trade, Industry and Energy, Korea, under grant 10052804, by the Basic Science Research Program within the Ministry of Science, ICT, and Future Planning through the National Research Foundation of Korea under grant 2017R1A2B4006460, and by Samsung Electronics.
© 2019 American Chemical Society.
- Fermi-level pinning
- III-V semiconductor
- Schottky barrier height
- metal-induced gap state
- molybdenum disulfide
- source/drain contact
ASJC Scopus subject areas
- General Materials Science